Interior Lights Dimming Circuit Description. Chevrolet PJJ 2000

For 1990-2009 cars

The instrument panel lamps dimming circuits consist of the following:

• | The instrument panel lamp dimmer switch

• | The body control module (BCM)

• | The individual component lamps

The BCM supplies voltage to the instrument panel dimming lamps through CKT 8 when it receives a parklamp-on signal from the parklamp switch (CKT 9). The intensity of the lamps is controlled by the instrument panel lamp dimmer switch and the BCM. The BCM provides voltage to the dimmer switch through CKT 230 and a signal return (ground) through CKT 719. The instrument panel lamp dimmer switch consists of an internal potentiometer which varies the voltage to the BCM depending on the position of the dimmer wheel. The BCM uses this signal to control the intensity of the lamps by providing a pulse width modulated (PWM) signal to the lamps. When the BCM senses a minimum input voltage, it provides a maximum duty cycle signal to the lamps and vice-versa. Ground for the lamps is provided by the individual components.